<?php
$aa = [1=>2,2=>3,4=>5];
//$as = array_slice($aa,0,1);
$as = array_chunk($aa,2);
var_dump($as);
exit;
join($aa);
var_dump($aa);
exit;
$ad = array_keys($aa);
$ads = key($aa);
var_dump($ad);
var_dump($ads);
exit;
$a = 1;
$b = 2;

$a = $a + $b - $a;
$b = $a + $b - $a;
echo $b;
